Welshguy,
You could try Rotor Aviation at Long Beach in California. They more or less specialise in hour building Brits...or they did a few years ago I was there back in 2002, and they only had one R44, but things could well have changed by now. Unless it's changed the office number is 001 562 595 6867. Loads to see - Los Angeles, mountains, coast, Catalina Island, etc etc. And they'll arrange accommodation and car hire and everything for you if you want them to.